Today Government regulations require that ditches or trenches dug for installing such utility equipment as water and sewer pipes and the like be refilled according to certain guidelines and specifications. Principally such regulations aim at assuring that the dirt and soil used in the refilling operation is properly placed during refilling, which generally requires spreading approximately 6 inches of loose dirt or soil in the ditch or trench, followed by a tamping or packing operation. This is repeated until the ditch or trench is filled, and, therefore, it follows that in effect the ditch or trench is refilled in layers. By this process, it is assured that a generally stable soil profile of a generally uniform density throughout results.
Usually such ditches or trenches are approximately 3-foot wide and it is, therefore, appreciated that a substantial volume of dirt or soil is involved in a major project. One can readily appreciate the large amount of labor and time required to fill such ditches and trenches in major projects where a substantial portion of the work must be done by manual labor which is often required because the ditch or trench of a 3-foot width is relatively narrow, and it is very difficult to provide automatic earthworking equipment that is capable of performing the spreading and tamping operations within a 3-foot ditch properly and efficiently.